A method for preparing carbon fiber heat insulation board

Abstract

The present invention relates to the technical field of composite materials, and in particular to a method for preparing a carbon fiber thermal insulation board. First, a carbon fiber prepreg is prepared for use; a mold is pretreated; based on the parameters of the carbon fiber thermal insulation board, the carbon fiber prepreg is laid layer by layer along the size of a female mold cavity of a pressing mold; the male mold of the pressing mold and the female mold of the pressing mold are molded together, and pressurized and heated for curing; then, after the mold is cooled to room temperature, the product is demoulded, taken out, and burrs are removed to obtain a carbon fiber thermal insulation board. In this way, the technical problems in the prior art that the processing process of metal thermal insulation materials is complicated, resulting in difficulty in ensuring processing accuracy and poor product consistency, while the utilization rate of metal materials is low, and the metal surface needs to be treated with anti-oxidation and corrosion, which increases the production cost, are solved.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, and in particular to a method for preparing a carbon fiber heat insulation board. Background Art

[0002] Computers and other electronic devices generate a lot of heat during operation, and effective thermal insulation structures are needed to block the disorderly diffusion of heat and achieve directional heat dissipation of the chassis. For the heat dissipation generated above, existing methods use metal thermal insulation materials, such as aluminum alloy and alloy steel, which have certain strength and thermal conductivity.

[0003] However, the processing of metal insulation materials is complicated, which makes it difficult to ensure processing accuracy and poor product consistency. At the same time, the utilization rate of metal materials is low, and the metal surface needs to be treated with anti-oxidation and corrosion, which increases production costs. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a carbon fiber insulation board, aiming to solve the technical problems in the prior art that the processing process of metal insulation materials is complicated, resulting in difficulty in ensuring processing accuracy and poor product consistency. At the same time, the utilization rate of metal materials is low, and the metal surface needs to be treated with anti-oxidation and corrosion, which increases the production cost.

[0005] To achieve the above object, the present invention adopts a method for preparing a carbon fiber heat insulation board, comprising the following steps:

[0006] Preparing carbon fiber prepreg for standby use;

[0007] Pre-treat the mold;

[0008] Based on the parameters of the carbon fiber heat insulation board, the carbon fiber prepreg is laid layer by layer along the size of the female mold cavity of the pressing mold;

[0009] The male mold of the pressing mold and the female mold of the pressing mold are molded together, and pressurized and heated to cure;

[0010] After the mold is cooled to room temperature, the product is demoulded, taken out, and deburred to obtain the carbon fiber insulation board.

[0011] The process of preparing carbon fiber prepreg for standby use is as follows:

[0012] The multi-layer carbon fiber is pulled into the resin tank by a traction machine so that both sides of the multi-layer carbon fiber are soaked with resin. Then the traction machine continues to pull the multi-layer carbon fiber to the carbon fiber prepreg molding mold, and heats and pressurizes it for curing to obtain the carbon fiber prepreg.

[0013] Among them, the method of pre-treating the mold is as follows:

[0014] First, remove moisture, dust and dirt from the mold surface and fully dry the mold;

[0015] Gently wipe the sealer on the mold surface in the specified direction and order, and evenly apply it to the convex parts and corners of the mold;

[0016] Then apply the release agent: dip a small amount of release agent solution on one end of the sponge, and gently apply it on the mold surface in the specified direction and order. Apply the release agent again after the volatiles in the last application are completely evaporated;

[0017] After applying the release agent, check carefully to see if there are any uneven or missed areas, then place the mold in a well-ventilated place or in a drying room to dry.

[0018] When the carbon fiber prepreg is laid in the cavity of the female mold of the pressing mold, the aerogel thermal insulation material is laid in the middle layer of the carbon fiber prepreg.

[0019] Among them, in the process of closing the male mold of the pressing mold with the female mold of the pressing mold:

[0020] The mold closing process is divided into two steps. Before the male mold contacts the molded material, low pressure and fast operation are required.

[0021] After the male mold contacts the molding material, the mold closing speed should be slowed down and high pressure and slow speed should be used instead.

[0022] Wherein, when preparing carbon fiber prepreg:

[0023] Carbon fiber parameters: Torayca-T300

[0024] Prepreg type: unidirectional continuous carbon fiber (carbon fiber fabric)

[0025] Thickness: 0.15mm;

[0026] Unit weight: 170g / cm 2 ;

[0027] Prepreg curing temperature: 150℃;

[0028] Resin base content: 30%-40%.

[0029] Among them, when the male mold of the pressing mold and the female mold of the pressing mold are molded together, and pressurized and heated to solidify and press the carbon fiber insulation board:

[0030] The curing temperature is 80°C; the pressure is 4 kg; and the curing time is 2 hours.

[0031] Among them, after laying the carbon fiber prepreg, the carbon fiber prepreg needs to be preheated.

[0032] A method for preparing a carbon fiber thermal insulation board of the present invention, when used specifically, first prepares carbon fiber prepreg for use; pre-treats the mold; based on the parameters of the carbon fiber thermal insulation board, lays the carbon fiber prepreg layer by layer along the size of the female mold cavity of the pressing mold; the male mold of the pressing mold and the female mold of the pressing mold are molded together, and pressurized and heated for curing; then, after the mold is cooled to room temperature, the product is demolded, taken out, and burrs are removed to obtain the carbon fiber thermal insulation board. In this way, the technical problems in the prior art that the processing process of metal thermal insulation materials is complicated, resulting in difficulty in ensuring processing accuracy and poor product consistency, while the utilization rate of metal materials is low, and the metal surface also needs to be treated with anti-oxidation and corrosion, which increases the production cost, are solved.

[0033] The present invention uses carbon fiber prepreg as raw material, combined with precise mold design and operation process, which greatly simplifies the preparation process of the insulation board. The carbon fiber prepreg itself has good plasticity and formability, making the laying process more precise and controllable, effectively avoiding the complex and difficult-to-control process steps in the processing of traditional metal insulation materials, thereby significantly improving the processing accuracy and product consistency;

[0034] At the same time, compared with metal materials, carbon fiber materials have higher strength and lower density, which greatly reduces the volume and mass of materials required to achieve the same thermal insulation effect. In addition, the precise laying and efficient curing process of carbon fiber prepreg further reduces material waste and improves the overall utilization rate of materials. These advantages work together to significantly reduce production costs and improve economic benefits;

[0035] In addition, carbon fiber materials themselves have excellent corrosion resistance and oxidation resistance, and do not require additional anti-oxidation and corrosion treatment like metal materials. This feature not only simplifies the production process, but also avoids quality problems that may be caused by improper treatment, further improving the reliability and stability of the product;

[0036] The carbon fiber thermal insulation board prepared by the present invention not only has excellent thermal insulation performance, but also has the characteristics of light weight, high strength, and corrosion resistance, so that it can still maintain good performance in harsh environments such as high temperature, humidity, and corrosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1It is a schematic structural diagram of a female mold used in the method for preparing the carbon fiber heat insulation board of the present invention.

[0039] Figure 2 It is a schematic structural diagram of a male mold used in the method for preparing a carbon fiber heat insulation board of the present invention.

[0040] Figure 3 It is a schematic diagram of the structure after mold closing of the method for preparing the carbon fiber heat insulation board of the present invention.

[0041] Figure 4 It is a schematic diagram of preparing the aerogel thermal insulation layer of the present invention. DETAILED DESCRIPTION

[0042] Embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0043] See also Figure 1 to Figure 4 ,in Figure 1 It is a schematic structural diagram of a female mold used in the method for preparing the carbon fiber heat insulation board of the present invention. Figure 2 It is a schematic structural diagram of a male mold used in the method for preparing a carbon fiber heat insulation board of the present invention. Figure 3 It is a schematic diagram of the structure after mold closing of the method for preparing the carbon fiber heat insulation board of the present invention. Figure 4 It is a schematic diagram of preparing the aerogel thermal insulation layer of the present invention.

[0044] The present invention provides a method for preparing a carbon fiber thermal insulation board, comprising the following steps:

[0045] S101, preparing carbon fiber prepreg for standby use;

[0046] According to this specific embodiment, the multi-layer carbon fiber is pulled into the resin tank by a tractor, so that both sides of the multi-layer carbon fiber are impregnated with resin, and then the tractor continues to pull the multi-layer carbon fiber to the carbon fiber prepreg molding mold, and heats and presses to cure to obtain the carbon fiber prepreg;

[0047] When preparing carbon fiber prepreg:

[0048] Carbon fiber parameters: Torayca-T300

[0049] Prepreg type: unidirectional continuous carbon fiber (carbon fiber fabric)

[0050] Thickness: 0.15mm;

[0051] Unit weight: 170g / cm 2 ;

[0052] Prepreg curing temperature: 150℃;

[0053] Resin base content: 30%-40%.

[0054] S102, pre-treating the mold;

[0055] According to this specific implementation, the method of pre-treating the mold is as follows:

[0056] First, remove moisture, dust and dirt from the mold surface and fully dry the mold;

[0057] Gently wipe the sealer on the mold surface in the specified direction and order, and evenly apply it to the convex parts and corners of the mold;

[0058] Then apply the release agent: dip a small amount of release agent solution on one end of the sponge, and gently apply it on the mold surface in the specified direction and order. Apply the release agent again after the volatiles in the last application are completely evaporated;

[0059] After applying the release agent, check carefully to see if there are any uneven or missed areas, then place the mold in a well-ventilated place or in a drying room to dry.

[0060] S103, laying the carbon fiber prepreg layer by layer along the size of the female mold cavity of the pressing mold based on the parameters of the carbon fiber heat insulation board;

[0061] According to this specific embodiment, when the carbon fiber prepreg is laid in the cavity of the female mold of the pressing mold, the aerogel insulation material is laid in the middle layer of the carbon fiber prepreg;

[0062] At the same time, when laying carbon fiber prepreg, the ply structure design should avoid warping deformation caused by coupling effects such as bending, stretching, and torsion during the curing process. The ply design should consider the following aspects:

[0063] ⑴. The design of effective force transmission ply should ensure that the structure can transmit external loads in a certain direction most effectively and directly, thereby improving the bearing capacity, structural stability and resistance to impact damage.

[0064] ① For components that are mainly subjected to tension and compression, 0° ply is preferred;

[0065] 0° 90° 0°

[0066] ② For components that are mainly subjected to shear, it is best to use ±45° ply layup as the main feature;

[0067] +45° -45° +45°

[0068] ③. From the perspective of stability and impact resistance, the outer surface of the laminate should be laid at ±45°;

[0069] +45° -45° +45°

[0070] ④. In areas that may be subject to low-energy impact, fabric plies should be used on the outer surface, the proportion of ±45° plies can be increased, or a hybrid structure consisting of carbon-aramid and carbon-glass fibers can be used;

[0071] +45° fabric -45° +45° fabric

[0072] After laying the carbon fiber prepreg, the carbon fiber prepreg needs to be preheated.

[0073] S104, closing the male mold of the pressing mold with the female mold of the pressing mold, and applying pressure and heating to solidify;

[0074] According to this specific embodiment, during the process of closing the male mold of the pressing mold with the female mold of the pressing mold:

[0075] The mold closing process is divided into two steps. Before the male mold contacts the molded material, low pressure and fast operation are required.

[0076] After the male mold contacts the molding material, the mold closing speed should be slowed down and high pressure and slow speed should be used instead.

[0077] When the male mold of the pressing mold and the female mold of the pressing mold are combined, and the carbon fiber insulation board is pressed and cured by pressurization and heating:

[0078] The curing temperature is 80°C; the pressure is 4 kg; and the curing time is 2 hours.

[0079] S105, after the mold is cooled to room temperature, the mold is demoulded, the product is taken out, and the burrs are removed to obtain the carbon fiber insulation board.

[0080] After the pressing is completed, the mold needs to be cleaned and post-processed;

[0081] Clean the mold as follows:

[0082] Since some residual molding materials and burrs may remain in the mold during molding, the mold must be cleaned after each molding. If the attachments on the mold are too strong, you can use a copper sheet to clean it, or wipe it with a polishing agent, etc. After cleaning, apply a release agent for the next molding.

[0083] The post-processing is as follows:

[0084] After demoulding, molded products often need to undergo certain post-processing to meet the requirements of use. The first process is to remove burrs and flash from the products, which can be done by manual or mechanical grinding to improve the appearance quality of the products; in addition, the products often need to undergo necessary mechanical processing, such as drilling and tapping. Since composite products are very sensitive to mechanical processing, it should be avoided as much as possible. If holes need to be opened, it can be solved by setting a core in the mold. For tapping, the threads can be directly formed on the molded products by setting a core with threads or a ring with internal threads.

[0085] A method for preparing a carbon fiber thermal insulation board of the present invention is used. When it is used, first, a carbon fiber prepreg is prepared for use; the mold is pretreated; based on the parameters of the carbon fiber thermal insulation board, the carbon fiber prepreg is laid layer by layer along the size of the female mold cavity of the pressing mold; the male mold of the pressing mold and the female mold of the pressing mold are molded together, and pressurized and heated for curing; then, after the mold is cooled to room temperature, the product is demolded, taken out, and burrs are removed to obtain a carbon fiber thermal insulation board. In this way, the technical problems in the prior art that the processing process of metal thermal insulation materials is complicated, resulting in difficulty in ensuring processing accuracy and poor product consistency, while the utilization rate of metal materials is low, and the metal surface also needs to be treated with anti-oxidation and corrosion, which increases the production cost, are solved.

[0086] The present invention uses carbon fiber prepreg as raw material, combined with precise mold design and operation process, which greatly simplifies the preparation process of the insulation board. The carbon fiber prepreg itself has good plasticity and formability, making the laying process more precise and controllable, effectively avoiding the complex and difficult-to-control process steps in the processing of traditional metal insulation materials, thereby significantly improving the processing accuracy and product consistency;

[0087] At the same time, compared with metal materials, carbon fiber materials have higher strength and lower density, which greatly reduces the volume and mass of materials required to achieve the same thermal insulation effect. In addition, the precise laying and efficient curing process of carbon fiber prepreg further reduces material waste and improves the overall utilization rate of materials. These advantages work together to significantly reduce production costs and improve economic benefits;

[0088] In addition, carbon fiber materials themselves have excellent corrosion resistance and oxidation resistance, and do not require additional anti-oxidation and corrosion treatment like metal materials. This feature not only simplifies the production process, but also avoids quality problems that may be caused by improper treatment, further improving the reliability and stability of the product;

[0089] The carbon fiber thermal insulation board prepared by the present invention not only has excellent thermal insulation performance, but also has the characteristics of light weight, high strength, and corrosion resistance, so that it can still maintain good performance in harsh environments such as high temperature, humidity, and corrosion.

[0090] The structure of the die forming mold is as follows:

[0091] Female mold

[0092] like Figure 1 As shown below: The working surface of the female mold is concave. The composite material products produced by the female mold have smooth outer surfaces and accurate dimensions. However, the female mold with deep concave surface is inconvenient to operate, difficult to exhaust, and difficult to control quality. The female mold is often used to produce products with high requirements on the outer surface, such as casings.

[0093] Male mold

[0094] like Figure 2 As shown: The working surface of the male mold is convex, as shown in the figure below. The inner surface of the product produced by the male mold is smooth, the size is accurate, the operation is convenient, the quality is easy to control, and it is easy to ventilate. Most of the layer laying processes use male mold forming.

[0095] The characteristics of carbon fiber are as follows:

[0096] 1. High specific strength and large specific modulus

[0097] Specific strength is the ratio of a material’s strength to its density;

[0098] Specific modulus is the ratio of a material's modulus to its density.

[0099] Specific strength and specific modulus are important indicators for measuring the load-bearing capacity and stiffness performance of structural materials. Structural materials of the same quality have higher specific strength and greater load-bearing capacity. The more commercial loads the structure can withstand, the stronger the economic performance of the material. The specific strength and specific modulus of commonly used materials are shown in the following table:

[0100] Table 1 Specific strength and specific modulus of commonly used structural materials

[0101]

[0102] 2. Low density

[0103] Carbon fiber has a low density, generally between 1.45 and 1.6 g / cm 3 .

[0104] Each carbon fiber is composed of thousands of smaller carbon fibers, with a single fiber diameter of about 5 to 8 microns. Internationally, it is divided into two categories according to performance and tow size: aerospace grade (small tow) and industrial grade (large tow). Small tows are 1K, 3K, 6K, 12K, and large tow fibers are above 24K. Each 1K is 1,000 single fibers, and 3K is 3,000 single fibers.

[0105] At the atomic level, carbon fiber is very similar to graphite, which is composed of layers of carbon atoms arranged in a hexagonal pattern. The difference between the two lies in the connection between the layers. Graphite is a crystalline structure, and its layer connection structure is loose, while carbon atoms are not a crystalline structure, and the connection between the layers is irregular, which prevents slippage and enhances the strength of the material. The density of ordinary carbon fiber is about 1500kg / m 3 .

[0106] 3. Good anti-fatigue performance and good damage safety performance

[0107] Fatigue failure is a low-stress failure caused by the formation and expansion of cracks under alternating loads. There are countless fiber / resin interfaces in composite materials, which can effectively prevent further crack expansion and thus delay the occurrence of crack failure.

[0108] Usually the fatigue strength limit of metal materials is 30%-50% of their tensile strength. However, the fatigue strength limit of carbon fiber resin-based composite materials is 70%-80% of their tensile strength.

[0109] 4. Good damping and shock absorption performance

[0110] The natural frequency of a stressed structure is not only related to the shape of the structure itself, but is also proportional to the square root of the specific modulus of the structural material. Therefore, composite structures have a higher natural frequency and are generally not prone to resonance. At the same time, the matrix and fiber interface of the composite material have a greater ability to absorb the energy of resonance, resulting in a high vibration damping of the material, and even if it vibrates, it can stop in a relatively short time.

[0111] For example, a vibration study of beams of the same size showed that an aluminum alloy beam took 9 seconds to stop, while a carbon fiber / epoxy composite beam only took 2.5 seconds to stop.

[0112] 5. Thermal performance

[0113] 1. Expansion coefficient

[0114] Carbon fiber has good high and low temperature resistance. It can still maintain a certain strength at a high temperature of 2000 in an inert atmosphere, and will not break even under liquid nitrogen (-230℃). Carbon fiber has a small thermal expansion coefficient and good dimensional stability. The axial thermal expansion coefficient of carbon fiber is negative (0~-1.6x10 -6 / ℃), the thermal expansion coefficient perpendicular to the axial direction is 22x10 -6 / ℃~32x10 -6

[0115] 2. Thermal conductivity (W / mK)

[0116] The definition of thermal conductivity is: how many W of energy can be transferred per unit length m, per K, and the unit is W / mK. "W" refers to the unit of thermal power, "m" represents the length unit meter, and "K" is the unit of absolute temperature. The larger the value, the better the thermal conductivity. Thermal conductivity refers to the amount of heat transferred through an area of ​​1 square meter in 1 hour under stable heat transfer conditions, when the temperature difference between the two surfaces of a 1m thick material is 1 degree (k, ℃), and the unit is watt / meter degree (W / mK, k here can be replaced by ℃).

[0117] Carbon fiber has high thermal conductivity and good thermal conductivity, with a thermal conductivity of 5 to 150 W / mK. The thermal conductivity is related to the composition structure, density, moisture content, temperature and other factors of the material, and the thermal conductivity decreases as the temperature increases.

[0118] 6. Electrical properties

[0119] Carbon fiber has good conductivity along the fiber axis. Its resistivity is related to the fiber type. The axial resistivity of polyacrylonitrile (PAN) carbon fiber is 3x10 -3 ~3x10 -4 Ω·Cm, the higher the degree of graphitization of carbon fiber, the better the conductivity, so the higher the modulus of carbon fiber, the lower the resistivity. In addition, carbon fiber can reflect electromagnetic waves and has good X-ray transmittance. Therefore, carbon fiber products have good electromagnetic shielding properties.

[0120] Table 2. Thermal and electrical properties of carbon fiber

[0121]

[0122] 7. Environmental resistance

[0123] Carbon fiber is relatively stable below 400°C in the air. Standard carbon fiber can be used for a long time at 316°C. The stability of carbon fiber increases with the degree of graphitization. The operating temperature of high modulus carbon fiber can reach 530°C.

[0124] Carbon fiber has excellent chemical corrosion resistance and is not corroded by general acids, alkalis, and solvents. It has better corrosion resistance than metal materials. Carbon fiber has good water resistance and resistance to moisture and heat (salt spray) aging in humid air (unlike glass fiber, which will not hydrolyze).

[0125] 8. Good processing technology

[0126] Different forming processes can be selected according to the shape, size, design requirements, production batch and component materials of the structural parts. It is particularly suitable for large-area integral forming, reducing the number of parts and connectors, saving time, materials, weight and costs. It is particularly suitable for the integral forming of chassis and shells, as well as the processing of various special-shaped structures and curved surface structural parts.

[0127] What is disclosed above is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A method for preparing a carbon fiber thermal insulation board, characterized in that: The steps include: Preparing carbon fiber prepreg for standby use; Pre-treat the mold; Based on the parameters of the carbon fiber heat insulation board, the carbon fiber prepreg is laid layer by layer along the size of the female mold cavity of the pressing mold; The male mold of the pressing mold and the female mold of the pressing mold are molded together, and pressurized and heated to cure; After the mold is cooled to room temperature, the product is demoulded, taken out, and deburred to obtain a carbon fiber insulation board.

2. The method for preparing the carbon fiber thermal insulation board according to claim 1, characterized in that: The process of preparing carbon fiber prepreg for use is as follows: The multi-layer carbon fiber is pulled into the resin tank by a traction machine so that both sides of the multi-layer carbon fiber are soaked with resin. Then the traction machine continues to pull the multi-layer carbon fiber to the carbon fiber prepreg molding mold, and heats and pressurizes it for curing to obtain the carbon fiber prepreg.

3. The method for preparing the carbon fiber thermal insulation board according to claim 2, characterized in that: The mold is pretreated as follows: First, remove moisture, dust and dirt from the mold surface and fully dry the mold; Gently wipe the sealer on the mold surface in the specified direction and order, and evenly apply it to the convex parts and corners of the mold; Then apply the release agent: dip a small amount of release agent solution on one end of the sponge, and gently apply it on the mold surface in the specified direction and order. Apply the release agent again after the volatiles in the last application are completely evaporated; After applying the release agent, check carefully to see if there are any uneven or missed areas, then place the mold in a well-ventilated place or in a drying room to dry.

4. The method for preparing the carbon fiber thermal insulation board according to claim 3, characterized in that: When the carbon fiber prepreg is laid in the cavity of the female mold of the pressing mold, the aerogel thermal insulation material is laid in the middle layer of the carbon fiber prepreg.

5. The method for preparing the carbon fiber thermal insulation board according to claim 4, characterized in that: In the process of closing the male mold of the pressing mold with the female mold of the pressing mold: The mold closing process is divided into two steps. Before the male mold contacts the molded material, low pressure and fast operation are required. After the male mold contacts the molding material, the mold closing speed should be slowed down and high pressure and slow speed should be used instead.

6. The method for preparing the carbon fiber thermal insulation board according to claim 5, characterized in that: When preparing carbon fiber prepreg: Prepreg type: unidirectional tape continuous carbon fiber; Thickness: 0.15mm; Unit weight: 170g / cm 2 ; Prepreg curing temperature: 150℃; Resin base content: 30%-40%.

7. The method for preparing the carbon fiber thermal insulation board according to claim 6, characterized in that: When the male mold of the pressing mold and the female mold of the pressing mold are combined, and the carbon fiber insulation board is pressed and cured by pressurization and heating: The curing temperature is 80°C; the pressure is 4 kg; and the time is 2 hours.

8. The method for preparing the carbon fiber thermal insulation board according to claim 7, characterized in that: After laying the carbon fiber prepreg, the carbon fiber prepreg needs to be preheated.

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